**3. The effects of chitosan characteristics and environmental conditions on flocculation of anaerobic sludge**

The flocculation efficiency of chitosan is sensitive to its characteristics. The most important characteristics of chitosan for flocculation efficiency are the degree of deacetylation and molecular weight since these are the main factors that affect particle size, particle formation and aggregation in the flocculation process. However, environmental conditions, i.e. pH and ionic strength, are also important in the dissolution and the charge of chitosan for flocculation process.
